Modem processors in computer systems experience dramatic swings in current demand. The change in current demand per unit time is characterized as di/dt. Dramatic increases and decreases in current demand may occur, for example, when a processor transitions between a state of inactivity such as a sleep state or a state where the processor is waiting for data and a state of activity such as a normal operation state or a state where intense computation must be performed. When a power regulation system in a computer system is unable to respond to an increase in current demand in a timely manner, the computer system may experience undesirable delays, halt, or reset. When the power regulation system in the computer system is unable to respond to a decrease in current demand in a timely manner, the components in the computer system may be damaged due to the resulting increase of the voltage.
In the past, designers placed decoupling capacitors between processors and power regulators. The output capacitors operated as energy sources and energy sinks to meet increases and decreases in current demand of the processors until the power regulation systems were able to detect the change in current demand and respond. This solution, however, is not effective in modem computer systems which have processors with increased power requirements. Present processors may experience an increase or decrease in current requirement by a factor of 40 where di/dt may be as high as 1 amp per nanosecond. The area on most processors and motherboards are unable to accommodate the number and size of the output capacitors that would be required to sufficiently respond to increases and decreases in current demand of this magnitude.